Abrasive wheel



May 19, 1931. T. LARSSON ABRASIVE WHEEL Filed Sept. 29, 1926 INVENTOR Uh ure .Cwrssun Wl-TNESSES BYg Q ATTORNEY Patented May 19, 1931 UNITED sTA s THURE LARSSON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR T NORTON COMPANY, j

PATENT oFricE v OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS I'ABRASIVE WHEEL Application filed September 29, 1926. Serial No. 138,495.

pends to a large extent upon the natureof the bond and the type and size of abrasive.

grain as well as the amount of each employed. The bond may be any one of various types, such as bakelit'e, rubber, silicate or shellac, but most commonly ceramicmaterials are employed which'are vitrified or' melted to a vitreous condition so-as to grip the surface of the abrasive grain firmly and,

to a limited extent, dissolve the surface material of the grain and unite therewith.

. The particular type of bond employed depends upon the type of grinding operation in which the wheel is to be used and whether a soft or hard grade wheel-is desirable or required. Soft wheels generally contain a smaller amount of {bond than the hard wheels and consequentlythe strength ofthe wheel is lower. r

Wheels constructed for heavy duty operations usually contain large abrasive grains united by a small amount of bond, producing a wheel having avery porous and open structure and a *relatively. lowstrength. Heretofore, it has been impossible to con eration ceramic or silicate bonded abrasive Wheels constructed in one piece should not be rotated at speedsexceeding about 6000 surface feet per minute. 1 I

Furthermore, in the manufacture of a large wheel composed of abrasive grain 501 united by a ceram c bond there is great struct a wheel, especially. a wheel" of large size or soft grade, which would effectively For example, it is danger of breakage of the wheel during the moulding and firing operation. The moulded article is friable and must be handled with great care to prevent injury thereto. When the moulded wheel is fired there is great danger'of cracking since the size of the article prevents even distribution of theheat, and abnormal strains may beset up therein. Hence, breakage of the large sizes of wheels is frequent and expected.

Heretofore, some relativelylarge abrasive wheels have been manufactured by assem bling a plurality of' bonded abrasive segments upon a drum or socalled wheel center. In following such practice it has been necessary for the user, when in-need of a new wheel, to'return the wheel center to the manufacturer of the abrasive segments for mounting thereon. This involves considerable expense and often unduly delays the d manufacturing operations of the user of the wheel. I

It is an object of the present invention to provide a stronger and safer-abrasive wheel composed of pieces'or segments of bonded abrasive grain which are appropri ately held together for shipment in the form of an integral wheel.

It is another object ofthe invention to provide an abrasive wheel constructed and arranged to minimize the efi'ect of the action of centrifugal force so that the wheel may be rotated at a more rapid rate than has heretofore been possible without danger of.

breakage or reduction in the desired factor of safety.

The present invention contemplates the provision of an improved wheel composed of a plurality of segments of bonded abrasive grain suitably held together byan an nular clamping device to form-an integral I I Wheel for shipment. The clamping. device should be constructed and arranged for read- 11y and conveniently securing upon. a wheel center as well as for holding the segments securely in a desired position to presentian abrasive surface. A facing of a suitable cementitious material maybe interposed between the engaging surfaces of each stag-- ment and the clamping device to provide a firm and rigid engagement therebetween. The clamping device may include a pair of annular rings on opposite sides of the segments held by an adjustable fastener eX- tending between the segments.

The inventionwill be more clearly understood from the following description in conjunction with the accompanying drawings; in which,

Fig. 1 is an elevational View of an abrasive wheel embodying the invention and 0peratively mounted upon a wheel center;

Fig. 2 is a partial sectional side elevational view of the same;

Fig. 3 is a'perspective view of a segment illustrating the method of securing the clamping device thereto;

Fig. 4 is a partial sectional-side elevational' view ofa modified construction of wheel embodyingthe invention;-. and

Fig. 5 is a perspective view of a segment employed in the construction of sucha wheel.

As illustrated in the drawings, a. wheel embodying'the invention may be formed of a plurality of ,bondedabrasive segments 10 so constructed that they may beheld in spaced relation in the form of an abrasive annulus or wheel by a suitable annular clamping device. As illustrated, the segments are provided with two concentric clampingshoulders 11 and 12 on its opposite exposed plane faces which slope outwardly toward each other in such a manner as to form a wedge shaped clamping lug,and this lug is shaped and arranged to be engaged by correspondingly shaped beveled surf-aces ona pair of clamping rings 18 located on opposite sides of the wheel. In order that the rings may make a firm and rigid engagement with the segments, facings 14 and 15 ofany suitable cementitious material, such as Babbitt metal, are interposed between the rings and the. upper and lower clamping, shoulders 11 and 12, these metal facings being ordinarily cast in place on the shoulders of the segmentsbefore they are assembled in position. The rings 13 of the clamping device are drawn towards the parallel plane surfaces of the segments by a fastener extending between the segments and adjustably' securedto the rings. A- suitable fastener may comprise a bolt 16 passing within grooves 17, as illustrated, in plane radial surfaces extending between two co-axial cylindricalsurfaces on the segments,

through openings 18' in the rings and adjustably. secured thereto by nuts 19. The spaces between the segments 10 may, be filled bya suitable cementitious material 21, such as-Babbitt metalor a mixture of sulfur and ground coke commonly known as lavasol. The clamping device-shouldbe constructed and arranged for readily and conveniently mounting upon a wheel center. In the construction illustrated each ring is provided with a lower wedge shaped portion 22 for clamping on a wheel center.

As illustrated in the drawing, the wheel may be mounted upon a wheel center comprising a hub 25 provided with a radially extending web 26 terminating in a periph eral surface 27 having an upwardly projecting wedge-shaped flange 28 on one side thereof and a removable clamping ring 28 on the other side against which the wheel of the" invention may rest. The clamping flanges 28 and 28' on the wheel center are shaped to lit the wedge shaped clamping rings 22, and they are adjustably secured together by bolts 29 passing through the inwardly projecting flange of the removable clamping ring 28 and the web 26 of the wheel center, whereby the abrasive ring may be securely and rigidly clamped in place.

By constructing the wheel of the invention of a plurality of bonded abrasive seg ments, which are held together inthe form.

of an integral wheel by the molten metal or sulfur compound flowed intothe crevices between the segments I have provided an abrasive annulus capable of being mounted as a unitary structure on a rotatable support. Also, by meansof the clamping rings 13 adjustably engaging opposite sides of the abrasive annulus, I- have provided reinforcing or strengthening support for the annulus which makes it feasible to transport the wheel without danger ofbreakage. This wheel has a most rigid construction which will withstand safely rotation at' speeds'substantially' greater than the maxinun safe allowable speed ofa solid. wheel of the same material,:that is, of the same bond. Furthermore, the wheel of the invention provides all the advantages ofza segmental wheel, and yet is preassembled in the form of an integral wheel for shipment so thatv the user may readily mount the same upon a wheel center. y

In the modified construction illustrated in Figs. 4 and :5 the abrasive segments 30 are relatively large and are supported for rotation at a-point ,as near to the abrading surface 31 as possible. The segments 30 are held together-in the form of an integral wheel and supported against the action of centrifugal ferce by a clamping device, such as rings 82 similar tothose previously described, engaging oppositely beveled clamping shoulders- 38 and 34 on the segments which form wed ed shape portions adapted to be engaged by the clamping. rings. These rings 32 are held the're'against by a fastener, such asa bolt 35,. extending between the segmentswithin a. groove 86' iens- 4a 3 I able cementitious material 39, such as Babbitt metal, is interposed between the engaging surfaces of the segments and the clamping device. The bottom portion of the clamping device is arranged with a wedgeshaped portion 40 for securing upon a suitable wheel center 41. in the same manner as described with reference to the, construction shown in Figs. 1 and 2.

The segments 30 are provided with beveled clamping shoulders 42 and 43 between the abrading surface 31 and the rings 82 for engagement by annular rings 44 and 45 respectively which are held thereagainst by bolts 46and 47 passing through grooves 48 and 49 respectively in the inner faces of the segments and secured to the rings 44 and 45 by nuts 50 and 51. Facings 52 and 53 of a suitable cementitious material,

such as Babbitt metal, may be interposed between the annular shoulders 42 and 43 respectively and the rings 44 and 45. Vhen the segments 30 wear down to the rings 44 and 45 the latter are removed. In this manner a wheel is provided having a long useful life as Well as one which is sup ported against the action of centrifugal force at a point as near as possible to the abrading or outer surface.

Having thus described my. invention, what I claim as new and desire to secure by Letters Patent is:

1. A segmental grinding wheel comprising a pluralityof abrasive segments arranged in the form-of an annulus, the annulus having on each of its opposite sides two opposed beveled clamping shoulders sloping in opposite directions and forming a wedge shaped clamping lug, a clamping plate on eachside of the annulus provided with beveled faces corresponding with the clamping shoulders on the annulus, and

means to draw the plates together, said.

parts being so arranged that the annulus is supported wholly by its beveled clamping shoulders.

2. A grinding wheel comprising an abrasive annulus having clamping shoulders on opposite sides thereof, clamping rings on opposite sides of the annulus in engagement 7 with said shoulders and serving-as an independent support for the abrasive body, means removably securing the rin s in position, and a rotatable wheel center having clamping members removably carrying the 7 rings.

A segmental grinding wheel comprising a lurality of abrasive segments arranged in the form of an annulus, each segment having on each of its exposed sides two beveled faces which vprovidea Wedge shaped clamping lug, a pair of supporting plates on opposite sides'of the annulus having beveled faces engaging the beveled faces on the lugs, means for adjustably clamping the plates'againstthe' sides of the wheel and ing a plurality of abrasive segments arranged 1n the form of an annulus, the annuhis having on opposite sides thereof two opposed clamping shoulders, shoes thereon having beveled faces sloping in opposite directions to form a wedge shaped clamping lug, two opposed clamping rings, having beveled faces engaging the shoes. on opposite sides of the annulus, and means to draw said rings towards each other to clamp the abrasive segments rigidly in position.

' 6. A segmental grinding wheel comprising a plurality of abrasive segments arranged in the form of an annulus, each segment having two clamping shouldersv on oppositesides thereof, a beveled facing inte gral with-each shoulder which is so arranged as to form a wedge shaped clamping lu clamping rings on opposite sides of the an nulus which have faces engaging the'beveled faces of said clamping lugs, means to draw said clamping-rings towards each other to secure said segments rigidly in position, and means for removably mounting the rings on a rotatable support.

7. 'A-segmental wheel comprising a series of abrasive segment-s arranged in theform of an annulus, a cementitious filler betwee the segments uniting them into an integral structure and reinforcing annular members removablyclamping against the sides of the segments and forming an abrasive body transportable independently of a wheel support, said structure having opposed beveled shoulders e-ngageable by clamping members for rotatably mounting the sameon a support. 1 L I I 8. A segmental grmding wheel comprising a plurality of abrasive-segments ar-.

ranged in the form} of an annulus, said an nulus having beveled clamping shoulders'on its oppositeside faces and a supporting face" on its inner. periphery, a facing shoe on each beveled jclamping shoulder and a cementitious filler between the segments which unites'them. into an integral body, and reinforcing members clamping against said faces and'forming acarrier for the annulus, which is independent of anyrotatable support, said members having provisions for mounting the annulus on a wheel center.

" 9."A segmental grindingwheel comprising a plurality of abrasive'seginents ar-' ranged in the formof an annulus, said annulushaving clamping shoulders onopp0- site sides thereof, a facing shoe: on each clamping shoulder, a filler of cementitious material between the segmentswhich unites them into an integral body and removable them into an integral body.

11. A grinding Wheel comprising an abrasive body having a series of concentric shoulders on each side thereof, a series of concentric, removable, clamping rings engaging the shoulders on each side of the wheel, means to secure the rings against the side faces of the wheel to reinforce the same during rotation thereof, and a Wheel center having clamping members removable independently of the rings which engage a set of said rings and support the abrasive body.

12. A segmental grinding wheel comprising a plurality of abrasive segments arranged in the form of an annulus, said annulus having a series of concentric beveled clamping shoulders on each side face thereof, a series of beveled clamping rings e11- gaging the clamping shoulders on each side 7 of the annulus, means to secure the opposed beveled rings together and hold the segments against breakage and means for removably and wedgin'gly mounting the inner set of clamping rings on a rotatable wheel center.

13. A grinding wheel comprising a series of abrasive segments arranged in the form of an annulus which has clamping shoulders on opposite sides thereof, clamping rings removably and adjustably secured against said shoulders and servingto support and reinforce the annulus, said rings having beveled clamping faces for mounting on a wheel center,and adjustable op-, posed clamping members wedgingly engaging the beveled faces on the rings and supporting the same.

Signed at WVorcestcr, Massachusetts, this 24th day of September, 1926.

. THURE LABSSON. 

